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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>
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  3. Another useful tool for monitoring database activity is the
  4. <code class="structname">pg_locks</code> system table. It allows the
  5. database administrator to view information about the outstanding
  6. locks in the lock manager. For example, this capability can be used
  7. to:
  8. </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
  9. View all the locks currently outstanding, all the locks on
  10. relations in a particular database, all the locks on a
  11. particular relation, or all the locks held by a particular
  12. <span class="productname">PostgreSQL</span> session.
  13. </p></li><li class="listitem"><p>
  14. Determine the relation in the current database with the most
  15. ungranted locks (which might be a source of contention among
  16. database clients).
  17. </p></li><li class="listitem"><p>
  18. Determine the effect of lock contention on overall database
  19. performance, as well as the extent to which contention varies
  20. with overall database traffic.
  21. </p></li></ul></div><p>
  22. Details of the <code class="structname">pg_locks</code> view appear in
  23. <a class="xref" href="view-pg-locks.html" title="51.74. pg_locks">Section 51.74</a>.
  24. For more information on locking and managing concurrency with
  25. <span class="productname">PostgreSQL</span>, refer to <a class="xref" href="mvcc.html" title="Chapter 13. Concurrency Control">Chapter 13</a>.
  26. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="monitoring-stats.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="monitoring.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="progress-reporting.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">27.2. The Statistics Collector </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 27.4. Progress Reporting</td></tr></table></div></body></html>
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